import React from "react"
function FormattedDate(props) {
    return <h2>现在是：{props.date.toLocaleTimeString()}</h2>
}
class State001 extends React.Component {
    constructor(props) {
        super(props);
        this.state = {date:new Date()};
    }

    componentDidMount() {
        this.timerID = setInterval(()=> this.tick(),1000);
    }

    componentWillUnmount() {
        clearInterval(this.timerID);
    }

    tick() {
        this.setState({
            date: new Date()
        });
    }

    render() {
        return (
            <div>
                <h1>状态示例：</h1>
                <FormattedDate date = {this.state.date}/>
            </div>
        )
    }
}
export default State001;